1. Field of the Invention
This invention relates generally to rolling carts or the like and more particularly to an improved bumper assembly therefor.
2. Description of The Prior Art
Rolling carts, of the type to which the present invention is directed, are frequently used in environments where sanitary requirements are of the highest order. For example, various types of rolling carts are used in hospitals for transporting medicines, linens, catheters, surgical and diagnostic tools, food, I.V. units, baskets and the like. Because of its environment, the rolling cart should be kept as clean as possible and should of course be susceptible to low cost maintenance procedures that will avoid or at least minimize the likelihood of contamination. The rolling carts must necessarily be highly mobile and are therefore provided with resilient bumpers to prevent damage of the contents of the truck and to prevent damaging walls and doors should the trucks be inadvertently mishandled. It has been found that one common source of contamination resides in the resilient bumper means since these bumper means, at least those which surround the lowermost support frame, are fairly close to ground level.
Those working in the field have recognized the problem and have attempted to provide solutions therefor but they have been generally unsuccessful, at least to the extent of providing rolling cart bumper means having smooth and unbroken surface areas that are less likely to attract and retain contaminants.
For example, one form of prior art utilized a length of a resilient material that was wrapped around and suitably secured to a support frame. It was found, however, particularly as a result of formation of the corners, that the resilient material would bunch up and would therefore present ridges or grooves that easily attracted contaminants and which were difficult to clean. Moreover, with this first type of prior art bumper there was the problem of the resilient material cracking at the corners, particularly after extended usage. The cracks in the corners, of course, would easily accommodate small particles of dirt which could then become packed in and therefore very difficult to clean. In addition, the cracked and worn corners of this first type of prior art bumper was unsightly. It should be further noted that where bumpers are adhesively secured, they are difficult to replace without considerable skill and special equipment.
In order to overcome the problem inherent in the first form of prior art structure described hereinabove, molded side and end resilient bumper strips were provided in combination with molded, L-shaped corner bumper members. The molded bumper strips and the molded corner bumper members, represented by this second form of prior art were fastened to the support frame by means of threaded fasteners. In order to accommodate the shanks and heads of threaded fasteners, the prior art bumper strips and bumper corner members were suitably counterbored. While the molded corner bumper members did overcome the problem of cracking at the corners of the bumper assembly, still another problem was raised by the counterbored holes.
Obviously, if the counterbored holes are to receive fasteners, both of the diameters of the counterbored holes must be larger than the head of the fastener and the shank of the fastener. This is to accommodate normal tolerances in both the molding operation of the corner bumper members and the normal tolerance variations found in fasteners. Because the two diameters in the counterbored holes must necessarily be oversized in order to permit easy insertion and removal of the fasteners, the resulting play of the fastener in its respective counterbored hold provided recesses that could very easily accommodate dirt particles. In addition, it will be readily apparent that it was extremely difficult to maintain the oversized, counterbored holes in a clean condition.
A further problem inherent in the prior art molded corner bumper means also relates to the oversized holes that were required for the fasteners. Because the holes were oversized there would necessarily be some limited movement of the molded corner bumper means with respect to the support frame and to the adjacent side and end bumper strips and this too resulted in crevices that could easily accommodate dirt particles. In addition, if the fit of the corner bumper means with respect to the size and end bumper strips was sloppy, as was frequently necessitated by virtue of the oversize, counterbored holes, there would be some loss of aesthetic appeal as well.